The present invention relates generally to a tension and anti-recoil mechanism for a cable tie tool, and more specifically, to such a mechanism for limiting the tension applied to the cable tie by the tool and limiting the re-coil of the tool when the cable tie is cut.
Cable ties are used to bundle or secure a group of articles such as electrical wires or cables. Cable ties of conventional construction include a cable tie head and an elongate strap extending therefrom. The strap is wrapped around a bundle of articles and thereafter inserted through a passage in the head. The head of the cable tie typically supports a locking element which extends into the head passage allowing the strap to be inserted through the passage but preventing retraction of the strap through the passage in the head. Two longitudinally separated portions of the strap are thereby secured to the head to define a loop for holding together the group of articles.
In use, the installer manually places the tie about the articles to be bundled, inserts the strap through the head passage and then manually tightens the tie about the bundle. Further tightening of the cable tie, which increases the tension in the strap thereof, may be provided by a cable tie tool.
One type of such a cable tie tool includes a housing which is generally pistol-shaped where the housing has a barrel into which the strap may be inserted for application of the tension. The housing has a grip which depends from the barrel.
Typically, cable tie tool are most effective when new and during a reasonable period of use thereafter. After prolonged use of a cable tie tool, the effectiveness thereof normally decreases. Such decreased effectiveness may result from a reduction in the quality of the blade which is supported, typically within the cable tie tool, and displaced to cut the strap of the cable tie. Such a reduction in the quality of the blade normally results in decreased quality of the severing of the strap.
Decreased effectiveness of the cable tie tool from prolonged use thereof may also result in increased force being required to close the trigger mechanism of the cable tie tool. The trigger mechanism is mechanically coupled to the blade such that closure of the trigger mechanism is required to displace the blade sufficiently to cut the strap of the cable tie. Such closure of the trigger mechanism is typically provided by grasping of the trigger mechanism and grip of the cable tie tool within the hand of the operator and the hand being squeezed or closed to pivot the trigger mechanism toward, and possibly into direct engagement with, the grip. If such closure or squeezing is significantly resisted by trigger mechanism, which may result from the quality of the blade being reduced or from other factors, then the closing force required to be applied by the hand of the operator is increased. If the force required to be provided by the hand of the operator is sufficiently large, undesirable consequences to the hand of the operator may result, such as strain or fatigue thereof.
The amount of use of a cable tie tool is primarily dependent upon the number of cable ties which have been tensioned and cut by the tool. The actual number of such cable ties which have been tensioned and cut by a specific cable tie tool is normally not apparent from the tool itself. The date of manufacture of a specific cable tie tool will not necessarily provide an indication of the amount of use of the tool since a relatively new tool may have been extensively used to tension and cut a large number of cable ties. Conversely, a relatively old cable tie tool may have been rarely used to tension and cut a small number of cable ties. Accordingly, an accurate determination of the amount of actual use of a specific cable tie tool is normally difficult. Typically, a determination of the actual number of cable ties which have been tensioned and cut by a specific cable tie tool is made by estimate or not at all.